1. Field of the Invention
The present invention relates in general to an adjuster for adjusting the position of a seat belt holder installed in a motor vehicle, and more particularly to an adjuster for adjusting the height of a holder by which an uppermost end of a shoulder belt part of the seat belt is held.
2. Description of the Prior Art
In order to safely and comfortably fit a seat belt to a seat occupant, various types of seat belt position adjusters have been hitherto proposed and put into practical use. One of them is shown in FIGS. 13 and 14 of the accompanying drawings, which is applied to a three-point supported type seat belt and designed to adjust the height of an uppermost end of the shoulder belt part of the seat belt. More specifically, the adjuster adjusts the height of a through ring through which an upper portion of the shoulder belt part passes.
As is shown in FIG. 14, the conventional belt holder position adjuster comprises an elongate base member 501 which is formed with a plurality of latch holes 503 arranged in two rows. The base member 501 extends along a center pillar 302 of a motor vehicle body and is secured thereto by means of upper and lower bolts 505. Axially slidably disposed about the base member 501 is a box-like anchor member 507. The anchor member 507 is formed with a threaded hole (no numeral) with which a headed bolt 510 is meshingly engaged. The head is covered with a knob 509. The bolt 510 has, within the anchor member 507, a latch piece (not shown) pivotally connected thereto. The latch piece is formed with a pair of shank portions (not shown) which are latchingly engageable with a selected pair of the latch holes 503 of the base member 501. The anchor member 507 has further a nut 511 secured thereto. A pillar garnish 513 of plastic is attached to the center pillar 302 in a manner to conceal both the base member 501 and the anchor member 507. As is seen from FIG. 14, the pillar garnish 513 is formed with an elongate slot 513a. As is seen from FIG. 15, the pillar garnish 513 is further formed at its back side with two mutually facing guide grooves 515 and 515 which extend along side edges of the elongate slot 513a. A slide cover 517 of plastic is slidably held by the guide grooves 515 and 515 so that it slides along the elongate slot 513a while covering the same. The slide cover 517 is formed at its generally middle portion with larger and smaller openings (no numerals) through which the knob 509 and the nut 511 are passed and exposed to the outside of the pillar garnish 513. A through ring 519 is pivotally connected to the anchor member 507 by a bolt 521 secrewed to the nut 511. A cap 523 is fixed to the head of the bolt 521 to conceal the same. As is seen from FIG. 13, an upper portion of a shoulder belt part of a seat belt 301 passes through the through ring 519. A leading end of the shoulder belt part is led downard to an emergency lock type belt retractor (not shown) which is located at a lower portion of the center pillar 302.
Position adjustment of the through ring 519 is carried out in the following manner
First, the knob 509 is manually turned in a given direction about the axis of the bolt 505. With this, the latching engagement between the latch pawls of the latch piece and the paired latch holes 503 of the base member 501 becomes cancelled. Thereafter, the anchor member 507 is moved on the base member 501 upward or downward toward a desired position at which the through ring 519 provides a belt wearer with a safe and comfortable belt fitting. When the anchor member 507 comes to the desired position, the knob 509 is turned in a reversed direction to advance the latch pawls and cause the latch pawls to be latchingly engaged with adacent new pair of latch holes 503 of the base member 501. With this, the through ring 519 is fixed at a newly selected anchoring position.
However, as will be understood from the above description, the conventional position adjuster has the following drawbacks. First, it is difficult or at least troublesome to slide the anchor member 507 to adjust the position where the latch pawls of latch piece are in coincidence with a desired pair of the latch holes 503 of the base member 501. In fact, such position search should be made by using both hands awkwardly. Second, manipulation or turning of the bolt 210 requires a considerable force. This is troublesome to a woman. Thus, it may occur that complete latching is not provided between the latch bolt 210 and the base member 201. Of course, this is very dangerous.